1. Field of the Invention
The invention relates to a light source module and a projection apparatus. More particularly, the invention relates to a light source module and a projection apparatus having high brightness.
2. Description of Related Art
With development of display technology, in a projection apparatus, besides that an ultra high pressure lamp (UHP lamp) suitable for emitting white light can be used together with a color wheel to sequentially generate red light, green light and blue light, so that the projection apparatus can provide color images, in recent years, projection apparatus using red, green and blue light-emitting diodes (LEDs) as light sources is further developed.
In the projection apparatus using the LEDs as the light sources, beams emitted from the red, green and blue LEDs are combined through a light combination system, so that different color beams with different propagating directions can be guided to the same direction. Since brightness of such projection apparatus is determined by brightness of the LEDs, wherein the green LED serves as a main brightness contribution light source, the whole brightness of the projection apparatus is limited by a light emitting efficiency of the green LED. However, the light emitting efficiency of the existing green LED is relatively low, which is not suitable to serve as a light source of a high brightness projector (for example, greater than 2000ANSI lumens).
Moreover, most of the energy provided to the LEDs is converted into heat. Therefore, to achieve a high brightness projection effect, the projector must have a considerable size for providing a good heat dissipation effect, and the size of the projector is increased as the projection brightness is increased, which may lead to inconvenience in utilization.
In addition, several patents related to the projector are provided. For example, China Patent No. 101498401 discloses a light source apparatus including an exciting light source, an exciting material and a turntable. Moreover, Taiwan Patent No. 541834 discloses a laser projector, which uses a diffraction device to diffract laser beams with different colors to the same direction so as to form a combination beam.
U.S. Pat. No. 6,762,785 discloses a light source module including a red light source, a green light source, a blue-green light source and a blue light source. U.S. Patent Publication No. 20090153582 discloses a technique of using a laser light to excite red, green and blue phosphor powder to generate a three-color image beam. Moreover, U.S. Patent Publication No. 20090262308 discloses a technique of using an exciting beam to excite a phosphor material or phosphor powder, wherein the phosphor material is coated on a transparent substrate and the exciting beam continuously illuminates into the same area of the transparent substrate. U.S. Patent Publication No. 20090284148 discloses a technique of using an exciting beam to alternately excite a red and a green phosphor materials on a transparent substrate to alternately generate red beams and green beams, and a blue laser beam is used as a blue light source.